A. Field of the Invention
This invention pertains generally to locks, and more particularly to a lock assembly which is particularly suitable for use on rental storage spaces and the like.
B. Description of the Prior Art
In a space, rental storage it is desirable for the renter to have normal access to the space but for the owner to retain control over it. The renter is typically allowed to install his own padlock to which only he has a key. At times, however, it may be necessary for the owner to remove the padlock in order to get access to the space, for example in the case of an emergency. At other times, it may be necessary for the owner to lock the renter out of the space, for example in the event of a failure to pay rent.
U.S. Pat. No. 4,229,956 describes a lock mechanism which allows the owner to enter the space and to lock the renter out without disturbing a padlock installed by the renter. This mechanism has a hasp affixed to an axially extendable, rotatable bolt and a staple carried by a plate which can slide with the bolt. The slide plate is normally held in a fixed position by a second lock which is controlled by the operator. The renter can normally secure the space by locking the bolt to the slide plate with his own padlock which secures the hasp and the staple together in the normal manner. The owner can gain access to the space with the padlock in place by unlocking the second lock to release the slide plate and moving the slide plate and the bolt as a unit to retract the bolt. The mechanism also has a pin accessible from the back side of the door which the owner can engage to lock the bolt and the slide plate together independently of the renter's padlock. When the first owner-controlled lock is reengaged to lock the slide plate in place, the renter is locked out of the space even though he may remove his padlock. This mechanism represents a significant improvement over prior systems in which the renter's padlock had to be cut or otherwise broken to give the owner access to the space, and another padlock had to be installed in order to resecure the space or to lock the renter out of it.